In a medium skillet over medium heat, melt 3 tablespoons of butter. Add the shallots and season with salt and pepper. Sauté until soft and golden, about 10-15 minutes. Add the vinegar and sugar and continue to cook until brown and glazed, about 5-10 minutes. Remove from the heat; set aside.

In a separate large skillet, heat the oil over medium heat. Add the pancetta and cook until browned and crisp, about 5-7 minutes. Using a slotted spoon, remove the pancetta to a paper towel lined plate to drain; reserve the fat in the pan. Increase the heat to medium-high and add the sliced Brussels sprouts. Sauté until lightly browned at the edges-- about 5 minutes. Add 1 cup chicken broth and the remaining tablespoon of butter. Cover and cook for 3 minutes. Uncover and cook, stirring occasionally until the sprouts are tender, but still bright green and most of the liquid has evaporated-- about 3 minutes more. Add the shallots and pancetta; season with salt and pepper and toss to combine. Enjoy!